Automatic apparatus for making welted pockets

ABSTRACT

Automatic apparatus for making welted pockets comprising a sewing unit, a work plate slidable along a longitudinal axis, a presser work clamp integral with the work plate to which a piece of fabric is fastened, a center blade and two side pressers for clamping a piece of patch fabric onto the main piece of fabric after folding it according to a determined shape, and a lever system including a lever arm having an adjustable effective length for dirving the strokes of said pressers in order to vary the width of the strokes.

United States Patent 1 Bianchi AUTOMATIC APPARATUS FOR MAKING WEL'IED POCKETS [75] Inventor: Nereo Bianchi, Pavia, Italy [73] Assignee: Necchi S.p.A., Pavia, Italy [22] Filed:

[21] Appl. No.: 255,734

May 22, 1972 [30] Foreign Application Priority Data [451 July 17,1973

oTHER PUBLICATIONS Reece Series P W, Pocket Welting Machine, 2nd Edition by the Reece Corp.

Primary ExaminerH. Hampton Hunter Attorney- Stevens, Davis, Miller 8L Mosher prising a sewing unit, a work plate slidable alorig a longitudinal axis, a presser work clamp integral with the work plate to which a piece of fabric is fastened, a center blade and two side pressers for clamping a piece of patch fabric onto the main piece of fabric after folding it according to a determined shape, and a lever system including a lever arm having an adjustable effective length for dirving the strokes of said pressers in order 4 Claims, 3 Drawing Figures June 22, 197] Italy 42910 A/7l 52 US. Cl. 112/65 [51] Int. Cl D05b 3/10 [58] Field of Search 112/65, 70, 74, 76, 112/264 [56] References Cited UNITED STATES PATENTS to vary the width of the strokes.

2,573,359 10/1951 Rich 112/65 AUTOMATIC APPARATUS FOR MAKING WELTED POCKETS The present invention refers to an apparatus for making welted pockets comprising a sewing unit, a work plate reciprocally slidable along the unit longitudinal axis, a piece of main fabric being locked thereto by a work clamp which is integral with the work plate during such longitudinal movement, a center blade and two side pressers suitable to fold a piece of patch fabric and successively lock it onto the piece of main fabric after folding according to a predetermined shape.

In order to fold the path fabric and fix it to the main fabric, with apparatus known in the art, first the inverted T-shaped center blade descends onto the piece of patch fabric which extends across the open side pressers. These side pressers then close laterally, thereby locking the patch fabric against the vertical portion of said center blade.

Then two parallel stitch lines are formed on the two superimposed fabrics by virtue of the work plate performing a stroke while a cutter carried by the needle bar makes a cut in the fabric between the two stitchmgs.

Side pressers, moving together with the work plate and work clamp during stitching formation, have two parallel grooves through which the sewing needles penetrate.

The center blade, which is displaceable in only a vertical direction to reach the raised loading position and the lowered sewing one, has two openings for needles to pass in correspondence with the grooves formed in the side pressers.

In order to vary the welt width, that is the distance between the two stitchings and the welt slit, in the machines already known in the art, apart from the necessary substitutions of certain members such as the needle clamp and the two needles, the throat plate, the center blade and moreover the variation of the position of the hooks, it was necessary to replace some members provided in the driving kinematic chain thereof, this being an operation requiring a lot of time and the intervention of skilled operators. Naturally, the stroke of the side pressers must be varied in correspondence with the different corresponding center blades which have a larger horizontal tab width for the larger welt widths.

The loading position of the side pressers must be varied in order to allow for the center blade raising over the side pressers during unloading and loading of the piece of fabric. On the other hand, choosing the largest loading position as the extreme lateral position of the side pressers, thereby adapting to all center blade sizes, would cause bad fabric folding in the case where center blades having a small horizontal tab width are used.

A principal object. of this invention is to provide means for obtaining the adjustment of the width of the stroke of the side pressers quickly and in an easy manner by non-skilled workmen. In order to achieve the object mentioned above, the technical problem to be solved was to insert a simple adjusting mechanism into the kinematic chain provided to drive the side pressers.

The invention is characterized in that the kinematic members driving the side pressers strokes comprise a lever system having a lever arm adjustable for varying the stroke width.

More particularly the invention is characterized in that the lever system is formed by a first arm having a fixed length connected with a pneumatic motor and by two parallel arms in which circumferential outline slots are formed along which pins can be adjustably fixed by means of screws. These pins are connected to ball joints fixed to their respective rods driving the side pressers by their oscillations. A preferred embodiment will be apparent from the following description and drawings in which:

FIG. 1 is a sectional front view of the apparatus of the invention; a

FIG. 2 is a section view of the apparatus of FIG. I along line 2--2;

FIG. 3 is a detail of the pneumatic layout operating the machine.

Referring first to FIG. I, a sewing machine 10, provided to make welted pockets, comprises a bed 11, a base 12, a standard 13, an arm 14 extending parallel to the bed 11 and a head 15, a needle bar 16 projecting from the head carrying a pair of needles l7 suitable to form two longitudinal parallel stichings and a cutter 18 carried by needle bar 16 and for making a slit parallel to the stitchings.

Two pulleys 20 and 21 are mounted at one end of a main shaft 19, mounted in the lower portion of arm 14. Pulleys 20 and 21 are adapted to :receive a drive belt, not shown in the drawings, connected with the sewing machine electric motor.

Displacement of the belt from pulley 20, which meshes with shaft 19, to pulley 21, which is idly mounted on the shaft, is obtained by a belt shifter con nected to a well-known lock mechanism generally indicated at 22. A rod 23 is connected with lock 22, and is adapted to slide in the upper part of arm 14.

The front end of rod 23 acts on opposed axes of two well-known thread tension devices 24 to neutralize the thread tension when the machine is locked.

A work plate 25 is slidable into bed 11 as shown in the sectional view of FIG. 2. The movement of work plate 25 is caused by a double acting pneumatic cylinder 26 and by a hydraulic fluid control cylinder 27 adapted to make the speed of work plate 25 uniform and adjustable. A work clamp 28, for clamping a piece of fabric (not shown) onto work plate 25, is drivingly connected with work plate 25 by a pair of levers 29 in order to follow its motion as is better detailed in our U. S. Pat. application Ser. No. 58,577, filed July 27, 1970 and now U.S. Pat. No. 3,653,345 dated Apr. 4, 1972, in which the members cited hereinabove and after are shown more particularly. A pair of side pressers 30 and 30 and a center blade 31 are provided for positioning a piece of patch fabric folded in a suitable way, onto the main fabric. Side pressers 30 and 30' are connected by means of levers 33 and 33 (FIG. 2) fastened to the lower portion of hubs 35 and 35' which can slide along the axis of a shaft 34; levers 29 of work plate 28 are integrally fixed to shaft 34. Shaft 34 is pivoted, free to rotate, into mountings 36 fixed to work plate 25.

Hubs 35 and 35' have U-shaped grooves 37 and 37 in their upper portion. Hubs 35 and v35' slide axially relative to shafts 38 and 38' disposed in grooves 37 and 37', when work plate 25, which carries mountings 36 and shaft 34, is displaced.

Two connecting rods 39 and 39' are fastened at one end to the ends of shafts 38 and 38' (FIG. 1). These connecting rods 39 and 39' are also integrally pivoted at their other ends to shafts 40 and 40 which are disposed parallel to shafts 38 and 38 and pivoted free to shift axially in mounts 41 and 41' and 42 and 42' relative to arm 14. In this manner shafts 38 and 38 oscillate around their respective shafts 40 and 40' thus causing the displacements of hubs and 35' along shaft 34. L-shaped levers 43 and 43' are fixed to the right end of shaft and 40 (FIG. 1 The arms 44 and 44' of levers 43 and 43' are fixed to shafts 38 and 38 so that the oscillation of shafts 40 and 40' corresponds to a uniform oscillation of shafts 38 and 38' as will be better explained hereinafter.

Further arms 45 and 45' of levers 43 and 43 are connected with ball joints 46 and 46' which are in turn connected with another pair of ball joints 48 and 48', respectively, by means of rods 47 and 47'.

Pins 40 and 49 are fastened to ball joints 48 and 48 and are slidable in slots 50 and 50' (FIG. 1) provided in arms 51 and 51 formed integrally in bushings 52 and 52', respectively. In order to allow this sliding action, bolts 72 and 72' are provided as pin securing members in the different slots positions. Each of bushings 52 and 52 is fastened at one end of a shaft 53 which can rotate in a mounting 54 fixed to bracket 55 (FIG. 1) of standard 13. A second arm 56 ending with a fork 57 projects from bushing 52. A lever 58 is pivotally mounted in fork 57, joining fork 57 to a block 59 (FIG. 1) fastened to rod 60 of a pneumatic cylinder 61 fixed to standard 13 and whose function will be described here inafter. Block 59 has an arm 62 to which one end of a rod 63 is fastened; a block 65 is locked to the other end of rod 63 by means of a screw 64. Block 65 carries two adjustable screws 66 and 67 acting against the rods of two valves 68 and 69, respectively.

Referring to FIG. 2, during the displacement of pins 49 and 49' in their respective slots 50 and 50', rods 47 and 47' rotate around ball joints 46 and 46' which remain stationary in the position shown in FIG. 2 corresponding to the closed position of the side pressers. This is because the pivot points of the ball joints to rods 45 and 45 are the center of circumferential arcs defined by slots 50 and 50'. The outside position of the side pressers will be varied by the displacement of pins 49 and 49' along slots 50 and 50'; on the contrary their inside position, shown in the drawing, will remain unvaried.

All ball joints fixed to the ends of rods 47 and 47' can be screwed thereto in order to correct possible side presser positioning errors. I

When a piece of fabric has been positioned onto .work plate 25, work clamp 28 is lowered by the operation of a pneumatic cylinder (not shown), actuating rod 70 and, through the latter, a pair of a lever groups indicated generally at 71, causing the pair of levers 29 and shaft 34 to oscillate.

Next, a piece of patch fabric is positioned on the side pressers 30 and 30. A suitable operator actuated treadle (not shown) operates a pneumatic cylinder that displaces from a position shown in FIG. 1 to a position shown in FIG. 3. As it moves, cylinder 75 causes a pin 79 to rotate by means of a rod 76, block 77 and lever 78, fixed to the end of pin 79. One end of a lever is also fixed to pin 79; the other end of lever 80 cooperates with a ring 81 of a rod 82 to which the center blade 31 is fixed.

Rotation of pin 79 in one direction causes center blade 31 to move downward.

Treadle actuation also causes switching of a four-way valve 85 by means of pilot 88 allowing cylinder 75 to move to the position of FIG. 3. At the end of its stroke the cylinder 75 opens a valve 83 allowing air flow coming from duct 84 connected with a slide valve (not shown) to reach cylinder 61 through valve 85, duct 86, valve 83 and duct 87. Cylinder 61 then attains the position shown in FIG. I to close side pressers 30 and 30' through the kindematic motion described above, the patch fabric is therefore folded into an inverted T- shape.

At the end of its stroke cylinder 61 opens valve 69 to permit air to flow through duct 89 in and through duct 90 to actuate a starting-pushbutton (not shown). At the end of a sewing cycle, work plate 25 actuates a valve (not shown) which in turn actuates pilot 91. Pilot 91 actuates switching valve 85, connecting duct 84 with duct 92 to allow air flow to valve 68 now closed; at the same time, valve 85 connects duct 84 to cylinder 61 through duct 93 and flow regulator 94. Cylinder 61 then returns to its rest position, thereby causing rotation of shaft 53, through lever 56, and the consequent downward movement of arms 51 and 51. This down ward movement of arms 51 and 51' causes, by means of ball joints 48 and 48', rods 47 and 47' and ball joints 46 and 46', the oscillation of L-shaped levers 43 and 43' with their respective shafts 40 and 40'. This oscillation of levers 43 and 43' with their respective shafts 40 and 40 causes a radial displacement of shaft 38 and 38' which, being placed into U-shaped grooves 37 and 37 displaces hubs 35 and 35 along the axis of shaft 34 towards the pair of levers 29. This displacement causes side pressers 30 and 30' to open. The operation of cylinder 61 causes valve 69 (FIG. 3) to close and valve 68 to open, thus allowing air flow through duct 92 to reach, through flow regulator 95, cylinder 75 which is driven to raise center blade 31 by means of the lever system described above.

By loosening nuts 72 and 72' it is possible to adjust,

- in a simple and fast manner, pins 49 and 49' of the respective ball joints 48 and 48' along slots 50 and 50 in such a way as to vary the vertical displacement of rods 47 and 47' and therefore the displacement of hubs 35 and 35' along the axis of shaft 34 and consequently to obtain a variation in the width of the welted pocket is obtained; more precisely an increase in the width of the patch fabric can be obtained by displacing pins 49 and 49' leftward, looking at FIG. 1, and a descrease in this width by displacing the pins rightward.

Causing pins'49 and 49' to assume non-aligned position, that is by choosing lever arms of different length, an asymmetry in the side pressers work position is obtained, thus allowing the formation of unsymmetrical welted pockets.

What is claimed is:

1. Apparatus for making welted pockets on a sewing machine, comprising:

a work plate mounted on the base plate of said machine and slidable along a longitudinal axis;

a presser work clamp connected to said work plate for movement therewith;

first and second side pressers mounted on said machine for folding and clamping a piece of patch fabric to a piece of main fabric clamped to the machine by said work clamp;

lever means connected to said pressers for moving said pressers into and out of a clamping position,

said lever means including a lever arm having an adjustable efiective length, wherein the width of the presser stroke is proportional to the length of said lever arm; and

a center blade connected to said lever means and movable into and out of a position for cutting said fabric in conjunction with the movement of said side pressers.

2. Apparatus according to claim I, wherein said lever means comprises: a first arm having a fixed length connected with a pneumatic motor; two parallel arms each having an arcuate slot formed therein; pins adjustably mounted in said slots; ball joints connected to said pins; rods connected to said side pressers; and means connecting said ball joints to said rods, wherein movement shafts forming guides for the movement of said hubs.

k t It 

1. Apparatus for making welted pockets on a sewing machine, comprising: a work plate mounted on the base plate of said machine and slidable along a longitudinal axis; a presser work clamp connected to said work plate for movement therewith; first and second side pressers mounted on said machine for folding and clamping a piece of patch fabric to a piece of main fabric clamped to the machine by said work clamp; lever means connected to said pressers for moving said pressers into and out of a clamping position, said lever means including a lever arm having an adjustable effective length, wherein the width of the presser stroke is proportional to the length of said lever arm; and a center blade connected to said lever means and movable into and out of a position for cutting said fabric in conjunction with the movement of said side pressers.
 2. Apparatus according to claim 1, wherein said lever means comprises: a first arm having a fixed length connected with a pneumatic motor; two parallel arms each having an arcuate slot formed therein; pins adjustably mounted in said slots; ball joints connected to said pins; rods connected to said side pressers; and means connecting said ball joints to said rods, wherein movement of said ball joints drives said rods to move said side pressers into and out of said clamping position.
 3. Apparatus according to claim 2, further comprising: hub members connected to said side pressers for movement together with said work plate; and second lever means connecting said hub members and said rods, said second lever means being operated by said rods.
 4. Apparatus according to claim 3, further comprising: two parallel shafts connecTed to said second lever means; wherein said hubs have U-shaped grooves formed therein for seating said parallel shafts, said shafts forming guides for the movement of said hubs. 